Bioactive marine secondary metabolite

In the search for bioactive marine secondary metabolites, drugs or drug leads with new modes of action, many invertebrates with new modes of action have been explored and tested in a variety of assays. Many marine natural products were found to be cytotoxic to an assortment of tumor cells, Some parts of the marine natural products were also found to be ichthyotoxic so as to defend themselves. Two examples, out of many, are the latrunculins and sarcophine. ... 

Given the number and diversity of secondary metabolites and their broad range of pre-ingestive bioactivities, it is of interest to speculate on the effect of these compounds (which can be present in plants and prey at concentrations that constitute approximately 20% of the dry tissue mass) once they are consumed. This chapter reviews what is known about the consumers post-ingestive response to marine secondary metabolites, focusing on marine herbivores, since... 

Specificity of molecular bioactivity and differentially induced defenses are only two examples of factors that can confound the interpretation of patterns at the macroscale. As our knowledge of marine systems continues to expand, the relative abundance of secondary metabolites in different geographic locations may be better understood. However, the literature supports the idea that local pressures and habitat, genetic composition, mode of response and metabolism of the algae play a significant role in shaping distribution patterns of secondary metabolites (e.g. Wright... 

The relative contribution to the cup of natural products by marine and terrestrial organisms is outlined in Table 9.1. Column entries are the phylum, class or order, number of species, biogenetic class of metabolites produced, their bioactivity level, and a qualitative indication as to the average molecular complexity (Whitlock 1998). The latter property receives closer attention in Table 9.II for specific molecular skeletons. These data warrant several conclusions. First, unusual secondary metabolites on land derive mostly fi-om green plants and arthropods, while in the sea are the algae, sponges, cnidarians, bryozoans, and ascidians that give most. This is true no matter if the molecular skeleton, or the actual metabolite, or even the bioactivity, is examined. 

Although terrestrial cyanobacteria are well-recognized producers of a wide range of bioactive compounds, marine species have received less attention until recently [159]. One of the most abundant and studied marine cyanobacteria is the pantropic Lyngbya majuscula (Oscillatoriaceae). A prolific producer of metabolites, it has so far yielded more than 110 secondary metabolites including compounds that exhibit antiproliferative, immunosuppressants, antifeedant and molluscidal activities [159,160]. Shallow water varieties of the cyanophyte contain N-substituted amides of 75-methoxytetradec-4E-enoic acid and of 7S-methoxy-9-methylhexa-dec-4 -enoic acid called malyngamides, a sub-class of which contains the 4-methoxy-3-pyrrolin-2-one system [158]. 

Thornton, M., Characterization of secondary metabolite bioactivity and production in bacteria associated with the antarctic marine sponge Isodictya setifera, Master s thesis, Florida Institute of Technology, Melbourne, FL, 1995. 

The marine environment is a vast resource for the discovery of structurally unique bioactive secondary metabolites, some belonging to totally novel chemical classes.8 Sessile benthic organisms including the Porifera, Cnidaria, Bryozoa, and Tunicata as well as marine algae have developed an arsenal of compounds which have been demonstrated to confer a competitive advantage in ecosystems characterized by extreme resource limitations. Interactions of these organisms at the genetic,... 

In spite of the difficulties reported, model primary culture systems have been established for shallow-water sponges that produce bioactive secondary metabolites. It has been demonstrated that cultured cells can be stimulated to divide by mitogens and retain the ability to synthesize bioactive compounds.115116 These successes suggest that, with a greater understanding of requirements for growth and compound production, invertebrate cell culture may become a viable source for bioactive marine natural products. 

Oceans provide enormous and diverse habitats for marine life. The distinct feature of marine life is the domination of invertebrates, which account for more than 95% of marine animals. Most marine invertebrates are sessile and soft-bodied and lack obvious physical defenses. Instead, they have evolved to defend by chemical means against predation and overgrowth by other fouling organisms. In fact, their secondary metabolites have unusual structural features and potent biologic activities, many of which are not found in terrestrial natural products. This review focuses on bioactive metabolites isolated mainly from marine invertebrates with a special emphasis on the uniqueness of marine natural products. 

Considerations of biodiversity as a source of new leads must address the tme biological origin of desired bioactive secondary metabolites. This is most certainly true when considering the marine environment as a source of new leads for the pharmaceutical and agricultural industries. 

ABSTRACT Marine invertebrates such as ascidians, sponges and others are a prolific source of bioactive secondary metabolites. We have isolated a variety of marine natural products from the Okinawan marine invertebrates by using the sea urchin egg assay. Our recent work, the isolation, structure determination and activities of chlorinated macrolides, sesterterpenic acids, a bromotyrosine derivative, acetogenin derived endoperoxides, diterpene alkaloids, sesquiterpene quinones and spiro-sesquiterpenes, is presented in this article. The syntheses of these metabolites are also described. 

This work reviews the recent literature (1990-early 2005) on antiviral secondary metabolites from marine organisms and microorganisms and reports a selection of results from more than one hundred bioactive compounds. Under the heading of each respective virus, this article reviews the research on the antiviral activity of extracts and compoimds present in the marine environment. This review demonstrated how far the search for new bioactive metabolites from... 

Abstract Diverse arrays of new bioactive secondary metabolites have been isolated from marine microorganisms and the number of publications in this area has greatly increased in recent years. In this review, the emphasis is placed on new compounds with antitumor, enzyme inhibitors, antivirus, and other bioactive metabolites from fungi, bacteria, actinomycetes, and cyanobacteria reported between 2000 and 2005. Supply is a major limitation in the development of marine bioproducts, and the methods for supplying these products are important. So in this review, the secondary major point is placed on the chemical synthetic studies. References of 390 structures and 263 citations are overall presented in this review. 

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